Method of making resilient batting



Patented June 25, 1946 I METHOD OF MAKING RESILIENT BATTING Clarence M.Clevenger and Lawrence B. ,Steele,

, Jr., Waynesboro, Va., assignors to E. I. du Pont 'de Nemours &Company, Wilmington, Del., a

corporation of Delaware No Drawing.- Application June 2, 1944, SerialN6. 538,554

This invention relates to the preparationof new lightweight, resilient,compression-resistant fibrous masses. More particularly, it relatestolightweight, resilient, compression-resistant ducing the originaldimensions thereof. These 1 Claim. (Cl. 117-140) and other objects willmore clearly appear here- I inafter.

We have now found that if a batting of freefall filaments of celluloseacetate having a low.

apparent density of the desired order, is impreg-. nated with apolyvinyl butyral dissolved in a liquid consisting of butyl acetate andtoluene or xylene, the hydrocarbon constituent preferably. being massescomprised of randomly distributed long- 5 present in majoramount, andthe solvent liquid, length, crinkled continuous filaments of cellulosethereafter removed, there results a batting 'of acetate and 'to themethod of forming these water-repellent fibers which batting is notsubmasses. l V stantially debulked and which,'in addition, is Incopending application Serial No; 477,012, characterized by an enhancedand permanent refiled February 25, 1943, there is disclosed the slli e.A ord n ly, the above stat j t preparation of new continuous filamentsof therare achieved by impregnating the bulk -batting moplastic organicsolvent-soluble filament-formof free-fall filaments of celluloseacetate-With ing organic material, which filaments are char-' P l vinybutyral i VBd n a l q i s st n acterized by having crimps lying atrandom in Of toluene xyl ne in major nt andbutyl three directions, by asurface having deeply cut acetate, expressing from the imp ed battingirregular disconnected pits or channels, and by excess impregnatingsolution, and thereafter dry having substantially no molecularorientation 8 the batting r y o r move the solvent along the filamentaxis. These filaments, heretherefrom and to form a batting ng a D013-inafter termed free-fall filaments, are formed vin l butyral resinuniformly distributed thereby extruding an organic solvent solution ofthe throughfilament-forming material, 9. g.'. an acetone soluh P lyv l uyr l re ins ef l for P poses tion of acetone-soluble cellulose acetate,in the Of this invention are those aining from 13-13% form of finestreams into an evaporative atmosp lyvinyl alcohol and from 0-5% polyv nephere and under a jet velocity sufliciently high to tote- A p lyvinylbutyral c nta nin 0% hymaintain the extruded material undercompresdroxyl calculated as Polyvinyl alcohol is p ferred. sive forceuntil the extruded material sets in the The concentration f po vinylbutyral in the form of self-Sustaining m m These m impregnating solutiondepends entirely upon the ments are t conveniently collected as amountof material to be left on the batting. density, bulky continuous battingwhichmay be Th i$ in tum is dependent P e e te t of used as such in avariety of ways However, m 39 molsture-repellence,compression-resistance,stifi. common t mqsi; bulky masses, loosely ness,rigidity and apparent density desired in the hered materials, battingsof free-fall filaments treated batting, and may be Varied from 2-5 havea relatively low degree of permanent resil- In 011191 to securePolyvinyl y al C tent in ience and when pressed or matted down they dothe higher Portion of this range, it may be ne not fully regain theiroriginal dimensions, 1. e., my Sublecl the batting to repeated impresethey are substantially debulked. Water .and Hating and dryingtreatments. moisture likewise have a debulking eflect on the The excessimpregnant of se. e rebattirlgs. Obviously, these characteristicsnecesmoved by any known expedient VB resarily serve to seriously delimitthe field of utilit moval of excess solution is most conveniently forthe battings and hence detract from their 0 accomplished by simplypressing th wet batting v u between squeeze rolls, or the equivalent,and this An object of this invention, therefore, is to proexpedient istherefore Preferred- Th squeeze vi filamentous masses of free f 11filaments f roll pressure should be such that the amount of cellulose atat whi h are light in weight solution retained in the batting is nomore than manently resilient, compression-resistant and twice the weightof the batting, calculated on a water-repellent, A further object 1 tprovide dry basis, since, if more than this amount is th d fgr treatinglow density filamentous left in the batting, the solution will drain tothe masses of free-fall filaments to impart thereto bottom While drying,t Causing a higher conpermanent resilience, resistance to compressioncentration of p l v y yr l to e left on the and water repellencywithoutsubstantially re- 5 underneath side of the batting. In those instanceswhere a more dense impregnated batting than can be obtained byincorporating the resin from a solvent consisting of toluene or xyleneand butyl acetate is desired, it may be obtained by adding to thesolution alcohol or any other Example A batting of free-fall filamentsof; acetone, soluble cellulose acetate (54.5% combined acetic acid) 2inches thick and having an apparent density of 2 lbs/cu. ft. was runthrough a solution consisting of 5% polyvinyl butyral (containing 10%polyvinyl alcohol), 10% butyl acetate and 85% xylene, and was thenpassed through squeeze rolls to remove excess solution, the pressurebetween the squeeze rolls being adjusted to press out solution in excessof twice the weight of the batting. Finally, the batting was subjectedto an; evaporative atmosphere of warm air which effected removal of thexylene and butyl acetateto'produce a batting containing about 8%polyvinyl butyral uniformly distributed therethroughgj The treatedbatting had a thickness of about 1.5 inches, an apparent, density of 3lbs/cu. it., was slightly stiff, and had a remarkable and lastlngresilience, i. e., even after repeated applications of pressure thebatting regained its dimensions immediately upon release of the pressurein each instance. In contrast to the untreated batting which suifers asubstantial reduction in bulk when contacted with water, the battingtreated as herein described is waterrepellent and remains substantiallyunaffected by water or an atmosphere having a. high moisture content.

The battings of this invention are particularly well suited for varioustypes of cushions and pads, and as heat and sound insulation, forfilters, and for a myriad of other uses where 'a lightweight, resilient,water-repellent, structurally stable batting is required.

-Moreover, these battings are attractive from the economic standpointfor the reason that they are produced merely by spinning andimpregnating. No carding operation, as in the preparation of cotton,rayon staplefiber, or wool batts, is necessary nor is a pulping orneedling operation required as in the case of wood pulp or-slsal .fiberbatts, respectively.

As many apparently widely different embodiments of this invention may bemade without departing from the spirit and scope thereof, it is to beunderstood that this invention isnot limited to the specific embodimentsthereof as defined in the appended claim.

We claim:

The method which comprises impregnating a batting of free-fallfilamentsof cellulose acetatewi'th a solution consisting of 5% ofpolyvinyl butyral containing 10% of polyvinyl alcohol, 10%

of butyl acetate and 85% of xylene, pressing said batting to removesolution in excess of two times 80 the weight of the batting, and dryingthe impregnated batting whereby to form a resilient,compression-resistant, water-repellent batting of free-fall filaments ofcellulose acetate having.

polyvinyl butyral resin uniformly distributed therethrough.

CLARENCE M. CLEVENGER. LAWRENCE B. STEELE, Ja.

except

